Truth in historical cases can be difficult to prove in a courtroom setting, particularly in situations involving only two parties and no witnesses.

In Australia, if the court can't determine who is telling the truth, the defendant (that is, the publication and source) will typically lose.

"Here, a plaintiff merely needs to show that they didn't really like what was published about them, and in the onus is on the publisher to prove the truth or otherwise of their publication, or try and get up on some other defences," Mr Bartlett says.

Those other defences include "qualified privilege" — in essence, a public interest provision within Australia's defamation laws — but that too is difficult to prove in court.

While the strict nature of Australia's defamation laws helps stop the media publishing material that is false and potentially damaging to an individual's reputation, it also creates a major barrier for victims of harassment or abuse at the hands of a high-profile individual, for instance, to coming forward.

Compare this with the US, where the onus is far more on the individual claiming to have been defamed.

It creates a climate where unproven allegations can be discussed with relative freedom in the media, but it also allows for allegations against someone as high-profile as Kevin Spacey to emerge.

The historical nature of the allegations against the Oscar-winning actor would render them almost extremely difficult to prove in a legal setting — and the cost alone of attempting to do so would typically be prohibitive.

Strength — and safety — in numbers

The ongoing joint ABC/Fairfax investigation into Burke is remarkable for many factors, not least because of the number of people who have corroborated a pattern of behaviour that support the allegations of harassment.

Mr Bartlett say the volume of sources — more than 50 and continuing to grow — would give great confidence to a pre-publication lawyer.

Crucially, many of the sources have been willing to forgo anonymity and speak publicly.

"There are lots of rumours that we hear daily, but the issue is does the media have the sources who are prepared to put their hand up and sources that are prepared to be named and prepared to stand up in court and give evidence should that person sue?" he says.

Few allegations receive such detailed attention though — and most cases are unlikely to have such a broad range of potential sources.

That may not stop a story from being published, and Mr Bartlett insists that it's "very rare" for a story to be completely buried.

"I have the right to recommend to an editor that an article be spiked, but it's more likely that I would make recommendations for a significant changes to the article to make it in a form that could be published," he says.

But the effect of those changes to avoid a defamation risk can potentially submerge a bigger and more important truth.